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At least 19 recordsLinked to original sources
PubMed1974

Utilization of gluconate by Escherichia coli. Uptake of D-gluconate by a mutant impaired in gluconate kinase activity and by membrane vesicles derived therefrom.

1. From Escherichia coli strain K2.1.5(c).8.9, which is devoid of 6-phosphogluconate dehydrogenase (gnd) and 6-phosphogluconate dehydratase (edd) activities, a mutant R6 was isolated that was tolerant to gluconate though still edd(-), gnd(-). 2. Measurements of the fate of labelled gluconate, of the conversion of gluconate into 6-phosphogluconate, and of the induction of gluconate kinase by the two organisms show that, although both inducibly form a gluconate-transport system, strain R6 is impaired in its ability to convert the gluconate thus taken up into 6-phosphogluconate; it was therefore used for study of the kinetics and energetics of gluconate uptake. 3. Suspensions of strain R6 induced for gluconate uptake took up this substrate via a ;high affinity' transport process, with K(m) about 10mum and V(max.) about 25nmol/min per mg dry mass; a ;low affinity' system demonstrated to occur in certain E. coli mutants was not induced under the conditions used in this work. 4. The uptake of gluconate was inhibited by lack of oxygen and by inhibitors of electron transport; such inhibitors also promoted the efflux of gluconate taken up. 5. Membrane vesicles prepared from strain R6 also manifested these properties when incubated with suitable electron donors, at rates similar to those observed with whole cells. 6. The results indicate that the active transport of gluconate into the cells is the rate-limiting step in gluconate utilization by E. coli, and that the mechanism of this process can be validly studied with membrane vesicles.

Amobarbital↗
PubMed1975

Utilization of gluconate by Escherichia coli. A role of adenosine 3':5'-cyclic monophosphate in the induction of gluconate catabolism.

1. Cultures of Escherichia coli growing on gluconate use both gluconate and glucose when glucose is added. 2. Glycerol-grown cells adapt to gluconate utilization even in media containing glucose as well as gluconate. 3. The rates of gluconate utilization by cells growing on a mixture of glucose and gluconate, and the specific activities of the gluconate uptake system and of gluconate kinase, are greater if adenosine 3':5'-cyclic monophosphate (cyclic AMP) is present in the medium than in its absence. 4. Growth on media containing gluconate and cyclic AMP is accompanied by the formation of methyl glyoxal and pyruvate, and progressive inhibition of growth. 5. A mutant devoid of adenylate cyclase activity (cya) grew well on glucose in the absence of exogenous cyclic AMP but grew only poorly on gluconate; neither the gluconate uptake system nor gluconate kinase was adequately induced. The addition of cyclic AMP promoted growth on gluconate and facilitated the induction of proteins required for gluconate catabolism. 6. Phage Pl-mediated transduction of cya+ into the cya-mutant also restored the wild-type phenotype in its ability to adapt to gluconate utilization.

Adenylyl Cyclases↗
PubMed1990

Behavior of Listeria monocytogenes in the presence of gluconic acid and during preparation of cottage cheese curd using gluconic acid.

Unrestricted or minimally restricted growth of Listeria monocytogenes strain V7 occurred 1) at 13 degrees C in tryptose broth with .125 or .25% gluconic acid or .1 to .3% glucono-delta-lactone, 2) at 13 degrees C in milk with .125 to 1.0% gluconic acid or .5 or 1.0% glucono-delta-lactone, 3) at 35 degrees C in tryptose broth with .125 to .5% gluconic acid or .1 to 5% glucono-delta-lactone, and 4) at 35 degrees C in milk with .125 to 1.0% gluconic acid or .5 to 1.5% glucono-delta-lactone. Limited growth of L. monocytogenes occurred 1) at 13 degrees C with .375 or .5% gluconic acid or .3 or .4% glucono-delta-lactone, 2) at 13 degrees C in milk with 1.5% glucono-delta-lactone, 3) at 35 degrees C in tryptose broth with .75% glucono-delta-lactone, and 4) at 35 degrees C in milk with 2.0% glucono-delta-lactone. Partial to complete inactivation of L. monocytogenes occurred 1) at 13 degrees C in tryptose broth with .75 to 1.5% gluconic acid or .75 or 1.0% glucono-delta-lactone, 2) at 13 degrees C in milk with 1.5% gluconic acid or 2.0 to 3.0% glucono-delta-lactone, 3) at 35 degrees C in tryptose broth with .75 to 1.5% gluconic acid or 1.0% glucono-delta-lactone, and 4) at 35 degrees C in milk with 1.5% gluconic acid or 2.5 or 3.0% glucono-delta-lactone. Milk containing L. monocytogenes was coagulated with gluconic acid, HCl, or rennet, and cottage cheese curd was prepared. After cooking, numbers of the pathogen in curd or whey from rennet-coagulated milk were reduced by ca. 1.5 and 2.5 orders, respectively. Small numbers of survivors appeared in curd but not in whey of HCl-coagulated milk. No survivors were detected in curd or whey of gluconic acid-coagulated milk.

Animals↗
PubMed1989

Effect of mutations causing gluconate kinase or gluconate permease deficiency on expression of the Bacillus subtilis gnt operon.

The gluconate (gnt) operon contains genes for a repressor of the operon, gluconate kinase, and gluconate permease. A nonleaky kinase mutation (gntK4) induced the gnt operon constitutively through interaction of the repressor with an inducer of gluconate which had been endogenously formed and accumulated in the cell owing to the complete deficiency of the kinase even in the absence of gluconate in the medium. In contrast, a nonleaky permease mutation (gntP9) never induced the operon by gluconate likely because it cannot give rise to its inducing concentration in the cell even in the presence of gluconate in the medium.

Bacillus subtilis↗
PubMed1975

Inducible gluconate permease in a gluconate kinase-deficient mutant of Escherichia coli.

Gluconate-resistant mutants were isolated from Escherichia coli strain DF 1070 deficient in phosphogluconate dehydrogenase (EC 1.1.1.44) and in phosphogluconate dehydrogenase (EC 4.2.1.12) which is inhibited by gluconate. Among the resistant mutants, AR 13 has been identified as a gluconate kinase (EC 2.7.1.12)-deficient strain. This mutant exhibits an inducible gluconate transport system capable of concentrating gluconate in the cytoplasm against a concentration gradient. The accumulated gluconate is subject to permanent turnover, and is not chemically modified. The kinetics of induction and deinduction indicate a single inducible component, rate limiting for the transport function, and the distribution of transport capacity among non-induced progeny of induced parents indicates that the inducible protein is membrane bound.

Biological Transport, Active↗
PubMed1985

Identification of the covalently bound flavins of D-gluconate dehydrogenases from Pseudomonas aeruginosa and Pseudomonas fluorescens and of 2-keto-D-gluconate dehydrogenase from Gluconobacter melanogenus.

An improved method is presented for the purification of 8 alpha-(N1-histidyl)riboflavin, 8 alpha-(N3-histidyl)riboflavin and their 2',5'-anhydro forms, which permits the isolation of sizeable quantities of each of these compounds from a synthetic mixture in pure form. Flavin peptides were isolated from the D-gluconate dehydrogenases of Pseudomonas aeruginosa and Pseudomonas fluorescens and from the 2-keto-D-gluconate dehydrogenase of Gluconobacter melanogenus. After conversion into the aminoacyl-riboflavin, the flavin in all three enzymes was identified as 8 alpha-(N3-histidyl)riboflavin. By sequential treatment with nucleotide pyrophosphatase and alkaline phosphatase, the flavin in each enzyme was shown to be in the dinucleotide form.

Carbohydrate Dehydrogenases↗
PubMed1979

D-Gluconate transport in Arthrobacter pyridinolis. Metabolic trapping of a protonated solute.

D-Gluconate uptake was studied in whole cells of Arthrobacter pyridinolis; the uptake activity was inducible, mutable and showed saturation kinetics (Km = 5 micrometer). Uptake of D-gluconate was not mediated by a phosphoenol-pyruvate : hexose phosphotransferase system, nor was it directly energized by ATP. A transmembrane pH gradient, delta pH, of --63 mV was generated by A. pyridinolis cells at pH 6.5, while at pH 7.5, delta pH = 0. Addition of 8 micrometer D-gluconate significantly reduced the delta pH. The transmembrane electrical potential, delta psi, which was --87 mV over a range of pH from 5.5 to 7.5, was unaffected by the presence of substrate. D-Gluconate accumulated at the same rate and as the protonated solute, at both pH 6.5 and 7.5. Experiments in which a diffusion potential was generated in cyanide-treated cells, indicated that the delta psi did not energize transport. Rather, the rate of D-gluconate uptake metabolism: (a) treatment of cells with valinomycin or nigericin, under conditions in which there was a loss of intracellular potassium, inhibited both D-gluconate uptake and the metabolism of pre-accumulated D-gluconate; (b) the effects of cyanide and azide on D-gluconate uptake were much more severe at pH 6.5 than pH 7.5, a pattern which paralleled the effects of these inhibitors on D-gluconate metabolism; (c) extraction and chromatography of intracellular label from D-gluconate uptake revealed that accumulation of unaltered D-gluconate was negligible; (d) a series of mutant strains with lower D-gluconate kinase activities also exhibited low rates of D-gluconate uptake; (e) spontaneous revertants of these mutant strains consistently regained both D-gluconate kinase activity and wild type levels of uptake.

Arsenates↗
PubMed1976

The regulation of transport of glucose, gluconate and 2-oxogluconate and of glucose catabolism in Pseudomonas aeruginosa.

1. The induction by glucose and gluconate of the transport systems and catabolic enzymes for glucose, gluconate and 2-oxogluconate was studied with Pseudomonas aeruginosa PAO1 growing in a chemostat under conditions of nitrogen limitation with citrate as the major carbon source. 2. In the presence of a residual concentration of 30mM-citrate an inflowing glucose concentration of 6-8 mM was required to induce the glucose-transport system and associated catabolic enzymes. When the glucose concentration was raised to 20mM the glucose-transport system was repressed, but the transport system for gluconate, and at higher glucose concentrations, that for 2-oxogluconate, were induced. No repression of the glucose-catabolizing enzymes occurred at the higher inflowing glucose concentrations. 3. In the presence of 30mM-citrate no marked threshold concentration was required for the induction of the gluconate-transport system by added gluconate. 4. In the presence of 30mM-citrate and various concentrations of added glucose and gluconate, the activity of the glucose-transport system accorded with the proposal that a major factor concerned in the repression of this system was the concentration of gluconate, produced extracellularly by glucose dehydrogenase. 5. This proposal was supported by chemostat experiments with mutants defective in glucose dehydrogenase. Such mutants showed no repression of the glucose-transport system by high inflowing concentrations, but with a mutant apparently defective only in glucose dehydrogenase, the addition of gluconate caused repression of the glucose-transport system. 6. Studies with the mutants showed that both glucose and gluconate can induce the enzymes of the Entner-Doudoroff system, whereas for the induction of the gluconate-transport system glucose must be converted into gluconate.

Citrates↗
PubMed1986

Predominance of gluconate formation from glucose during germination of Bacillus megaterium QM B1551 spores.

Metabolic pathways of glucose during germination of Bacillus megaterium QM B1551 spores were studied by using specifically labeled glucose and gluconate. The Embden-Meyerhof pathway, the pentose cycle, and the direct oxidation route of glucose to gluconate (the gluconate pathway) were all operative at this stage; among those, gluconate accumulation was most predominant, especially in the early stage. Potassium fluoride, an enolase inhibitor, abolished the catabolism by the Embden-Meyerhof pathway totally without affecting gluconate accumulation. Under these conditions glucose was exclusively oxidized to gluconate. Gluconate thus accumulated could be metabolized further via phosphorylation by gluconate kinase. Remarkable gluconate accumulation was also demonstrated in several other spores requiring alanine as an effective germinant. NADH formed by the direct glucose oxidation may serve as a initial ATP source to phosphorylate glucose in germinating spores.

Bacillus↗
PubMed1992

The metabolism of gluconate in Escherichia coli: a study in continuous culture.

The gluconate metabolism in Escherichia coli involves duplicate activities of transport and phosphorylation for gluconate. In both cases, these activities can be differentiated in vitro by their different affinities for the substrate. In addition, the two gluconokinases can be differentiated by their heat sensitivities. The technique of continuous culture was used to investigate the influence of the growth rate on this metabolism in an E. coli HfrG6 strain during gluconate-limited growth under conditions of high and low oxygen concentrations. The transport and phosphorylation for gluconate, induced when the cells are cultivated in media with gluconate were differently influenced by the culture dilution rate. These activities were induced under the two conditions investigated; however, the low affinity transport system for gluconate and the thermosensitive gluconokinase were not detected under conditions of high and low oxygen concentrations, respectively. The induction of the dehydratase was favoured under conditions of low oxygen concentration. The experimental data suggest that induction and repression work together to regulate the levels of these activities during gluconate-limited growth conditions. Furthermore, that an effector molecule distinct from gluconate might be involved in the induction of the dehydratase.

Bacteriological Techniques↗
PubMed1975

The uptake of glucose and gluconate by Pseudomonas putida.

The uptake of glucose and gluconate is under inductive control in Pseudomonas putida. Glucose, gluconate, and 2-ketogluconate were each good nutritional inducers of these transport abilities. Glucose and gluconate uptake obeyed saturation kinetics: the apparent Km for glucose was 6 mM and that for gluconate was 0.5 mM. Therefore, transport of both substrates appears to be mediated by enzyme-like carriers. Glucose and gluconate are parallel inhibitors for their uptake9 Strains selected for their inability totransport glucose were found to be deficient in gluconate uptake. The reverse was alsotrue: mutations affecting gluconate entry also blocked the uptake of glucose. These results demonstrate that a common carrier is involved in the uptake of both glucose and gluconate by P. putida cells.

Biological Transport↗
PubMed1987

Gluconate metabolism in germinated spores of Bacillus megaterium QM B1551: primary roles of gluconokinase and the pentose cycle.

The metabolic pathway of gluconate, a major product of glucose metabolism during spore germination, was investigated in Bacillus megaterium QM B1551. Compared to the parent, mutant spores lacking gluconokinase could not metabolize gluconate, whereas the revertant simultaneously restored the enzyme activity and the ability to metabolize it, indicating that gluconokinase was solely responsible for the onset of gluconate metabolism. To identify a further metabolic route for gluconate, we determined 14C yields in acetate and CO2 formed from [14C]gluconate, and found that experimental ratios of 14CO2/[14C]acetate obtained from [2-14C]gluconate and [3,4-14C]gluconate were not compatible with the ratios predicted from the Entner-Doudoroff pathway. In contrast, when CO2 release caused by recycling (approx. 30%) was corrected, the ratios almost agreed with those from the pentose cycle. Comparison of specific radioactivities in acetate also supported the conclusion that gluconate was metabolized via the pentose cycle, subsequently metabolized via the Embden-Meyerhof pathway, and finally degraded to acetate and CO2 without a contribution by the Krebs cycle.

Acetates↗
PubMed1979

[Investigations on the utilization of D-gluconate and D-glucono-delta-lactone in the metabolism of the normal and alloxan diabetic rat (author's transl)].

Radioactivity was measured in the blood of normal and alloxan diabetic rats, after the oral administration of [U-14C]gluconate and [U-14C]glucono-delta-lactone, respectively. Radioactivity was also measured in the intestinal contents and feces 5 h after ingestion of the radioactive materials, It was concluded that the lactone is better absorbed from the intestine than the gluconate anion. According to this enhanced membrane permeation and the higher concentration reached in blood, the space of distribution of the lactone is larger than that of gluconate (50 and 41% of body weight, respectively); a higher retention in tissues and a greater loss in urine was also observed after administration of the lactone. Incorporation into liver glycogen is also higher from the lactone than from gluconate after oral administration, particularly in diabetic animals. The initial deficit in the oxidation of gluconate compared to that of the lactone, caused by a lag period of 7 and 4 h, respectively, is completely compensated during the following 8-9 h. The oxidative turnover of gluconolactone and of gluconate is significantly enhanced in diabetic animals. The better utilization in diabetic metabolism is in part explainable by a rise of glycolytic intermediates in the liver, which are decreased in starvation and diabetes. The limiting step of gluconate metabolism is the initial phosphorylation. Possibilities are discufor the dietetic use of gluconic acid in the form of an apolar derivative (lactone, ester).

Animals↗
PubMed1986

Gluconate accumulation and enzyme activities with extremely nitrogen-limited surface cultures of Aspergillus niger.

Batch cultures of Aspergillus niger grown from conidia on a medium with high C/N ratio accumulated gluconate from glucose with a yield of 57%. During almost the whole time of accumulation there was no net synthesis of total protein in the mycelium but the activity per flask and the specific activity of glucose oxidase (EC 1.1.3.4) in mycelial extracts increased whereas both values decreased for glucose dehydrogenase (EC 1.1.99.10) 'gluconate 6-phosphatase' (cf. EC 3.1.3.1, 3.1.3.2), gluconokinase (EC 2.7.1.12), glucose 6-phosphate and phosphogluconate dehydrogenases (EC 1.1.1.49, EC 1.1.1.44), phosphoglucomutase (EC 2.7.5.1), and most enzymes of the Embden-Meyerhof pathway and the tricarboxylic acid cycle. Gluconate dehydratase (EC 4.2.1.39), gluconate dehydrogenase (EC 1.1.99.3) and enzymes of the Entner-Doudoroff pathway could not be detected. By cycloheximide the increase of glucose oxidase activity was inhibited. It is concluded that the high yield of gluconate was due mainly to the net (de novo) synthesis of glucose oxidase which occurred during protein turnover after the exhaustion of the nitrogen source, and which was not accompanied by a net synthesis of the other enzymes investigated. Some gluconate may also have been formed by hydrolytic cleavage of gluconate 6-phosphate.

Aspergillus niger↗
PubMed1987

The gluconate operon gnt of Bacillus subtilis encodes its own transcriptional negative regulator.

The gluconate (gnt) operon of Bacillus subtilis consists of four gnt genes; the second and third genes code for gluconate kinase (gluconokinase, EC 2.7.1.12) and gluconate permease, respectively. A fragment carrying the promoter of this operon (gnt promoter) and the first gene (gntR) was subcloned into a promoter probe vector (pPL603B). Repression of the expression of cat-86 gene, encoded in the vector portion of a constructed plasmid (pgnt21), that is under the control of the gnt promoter was removed by gluconate. The results of deletion analysis and of insertional inactivation of the gntR gene cloned in pgnt21 suggested that the product of the gntR gene, actually synthesized as a 29-kDa protein in vivo, is involved in repression of the gnt promoter. A 4-base-pair insertional mutation within the gntR gene constructed in vitro was introduced into the B. subtilis chromosomal gnt operon by use of linkage of the 4 base pairs to gntK10 in transformation. The introduced mutation gntR1 caused the constitutive expression of the gluconate kinase and gluconate permease genes. S1 nuclease analysis indicated that the mRNA of this operon is synthesized in the gntR1 strain and amounts of mRNA are not changed very much by gluconate, which acts as an inducer in the wild-type gene. These results strongly indicate that the gntR gene codes for a transcriptional negative regulator for the gnt operon.

Bacillus subtilis↗
PubMed1986

The characterization and cloning of a gluconate (gnt) operon of Bacillus subtilis.

The enzymes involved in gluconate utilization in Bacillus subtilis seemed to be gluconate permease and gluconate kinase. Several mutants unable to grow on gluconate were isolated. The mutations they harboured (gnt) were clustered between iol-6 and fdp-74 on the B. subtilis chromosome (a tentative map order of gnt-10, gnt-4, gnt-26, gnt-23 and gnt-9 was obtained). The gnt-10 mutation seemed to be located within the structural gene of the kinase, and the gnt-23 and gnt-26 mutations seemed to be within that of the permease. An EcoRI fragment (4.5 MDal) containing an intact gluconate (gnt) operon consisting of these two structural genes was cloned in phage phi 105 by prophage transformation and was mapped physically. The physical location of the mutations coincided with their order on the genetic map. The HindIII-A fragment (2.4 MDal), which corrects all the gnt mutations, was subcloned in plasmid pC194. The fragment contained the structural genes for the gluconate permease and kinase, but not the regulatory region of the gluconate operon.

Bacillus subtilis↗